/* Copyright (c) 2020 XEPIC Corporation Limited */
/*
 * Copyright (c) 2016 Martin Whitaker (icarus@martin-whitaker.me.uk)
 *
 *    This source code is free software; you can redistribute it
 *    and/or modify it in source code form under the terms of the GNU
 *    General Public License as published by the Free Software
 *    Foundation; either version 2 of the License, or (at your option)
 *    any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
 * USA.
 */

#include "latch.h"

#include <cassert>
#include <climits>
#include <cstdio>
#include <cstdlib>
#include <iostream>

#include "compile.h"
#include "schedule.h"

/* We need to ensure an initial output value is propagated. This is
   achieved by scheduling an initial value to be sent to port 3. Any
   value received on port 3 will propagate an initial value of 'bx. */

vvp_latch::vvp_latch(unsigned width) : en_(BIT4_X), d_(width, BIT4_X) {}

vvp_latch::~vvp_latch() {}

void vvp_latch::recv_vec4(vvp_net_ptr_t port, const vvp_vector4_t& bit,
                          vvp_context_t) {
  vvp_bit4_t tmp;

  switch (port.port()) {
    case 0:  // D
      d_ = bit;
      if (en_ == BIT4_1) schedule_propagate_vector(port.ptr(), 0, d_);
      break;

    case 1:  // EN
      assert(bit.size() == 1);
      tmp = en_;
      en_ = bit.value(0);
      if (en_ == BIT4_1 && tmp != BIT4_1)
        schedule_propagate_vector(port.ptr(), 0, d_);
      break;

    case 2:
      assert(0);
      break;

    case 3:
      port.ptr()->send_vec4(vvp_vector4_t(d_.size(), BIT4_X), 0);
      break;
  }
}

void vvp_latch::recv_vec4_pv(vvp_net_ptr_t ptr, const vvp_vector4_t& bit,
                             unsigned base, unsigned wid, unsigned vwid,
                             vvp_context_t ctx) {
  recv_vec4_pv_(ptr, bit, base, wid, vwid, ctx);
}

void compile_latch(char* label, unsigned width, struct symb_s arg_d,
                   struct symb_s arg_e) {
  vvp_net_t* ptr = new vvp_net_t;
  vvp_latch* fun = new vvp_latch(width);

  ptr->fun = fun;
  define_functor_symbol(label, ptr);
  free(label);
  input_connect(ptr, 0, arg_d.text);
  input_connect(ptr, 1, arg_e.text);

  vvp_vector4_t init_val = vvp_vector4_t(1, BIT4_1);
  schedule_init_vector(vvp_net_ptr_t(ptr, 3), init_val);
}
